Truing device for grinding wheels



Feb. 28, 1928;

1,661,041 c. J. IRWIN I TRUING DEVICE FOR GRIANDING WHEELS. 7

Filed March 2, 1925 2 sheets-sheet 1 Feb. 28, 1928.

v. 1,661,041 c. J. IRWIN TRUING DEVICE FOR GRINDING WHEELS ed rh2, 19 23 ZSheets-Sheet 2 Patented Feb. 28, 1928.

UNITED STATES CHARLES 3'. IRWIN, OF CHICAGO, ILLINOIS, ASSIGNOR TO ILLINOIS TOOL WORKS, OI CHICAGO, ILLINOIS, A. CORPORATION OF ILLINOIS.

Application filed March 2, 1923. Serial No. 622,275.

My invention relates to truing devices for grinding wheels, grinding points and the like, and the object of the invention is to provide a convenient apparatus which will permit of various adjustments and make 1t possible to produce a variety of contours 1n the article to be trued orv dressed. It is my purpose to provide a compact. and substantially unitary structure ca able of produc ng accurate work and con gurating abrasive elements of 'various shapes and s1 zes.

Another object is to render it easily possible to reproduce, if desired, any given angle.

In connection with this last objectit will be understood that it is colnmon practice to employ grinding wheels to work on hobs and cutters and other pieces of work where the surface to be ground must lie accurately at a definite angle. In order to effect this it is necessary that the acting surface of the grinding elements must lie at a definite angle.

One of my objects is to make it, poss ble,

after the proper angle for truing the grind ing element has once been determined, to

reproduce this angle as many tlmes as desired without requiring a resetting of the frame work of the apparatus. As a result of this feature of the invention different grinding wheels may be introduced into the apparatus one after the other and the same angle reproduced in every specimen without requiring a new angular adjustment each time. I accomplish my objects by the mechanism illustrated in the accompanying drawings in which 1 p Figure 1 is a top plan view of the apparatus as a whole.

Figure 2 is an elevation looking from the front of Figure 1. a

Figure 3 is an enlarged sectional view taken on the irregular line 3--3 F igure 6.

Figure 4. is an enlarged sectional view taken on the line 4-4 Figure 6.

Figure 5 is a sectional detail view on the irregular line 5-5 Figure 6.

Figure 6 is an enlarged plan view similar to Figure 1 but showing'certain of the parts in. anal section.

Like numerals denote like parts throughout the several views.

According to the illustrated design there is a pedestal 1 which forms a support for a shaft 2, which is held in position by a cap 4. The cap is held in place by wing nuts 6 which screw onto studs 8 which rise from the pedestal and project up through the cap. The cap thus forms a clamp which when tightened will prevent the shaft 2 from r0- ta-ting aboutits axis. By loosening the clamp the shaft may be ad usted to any desired angular position.

A frame 10 is secured to the projecting ends of shaft 2 and is held rigid on it by pins 12 or other appropriate means. This frame has a split hub 14 adapted to support the casing 16 of a spindle bearing. Hub 14 is clamped onto the spindle casin by a clamping screw 18 and nut 19.. By hacking off the nut the hub will spring open far enough to permit casing 16 to be shifted longitudinally for adjustment purposes. A

spindle 20 is journaled in casing 18 and at one end has attached to it a grinding Wheel 22. This particular grindin wheel is shown in frusto-conical form suitable for grindin a hob 24 indicated in dotted lines at the le t of Figure 6. It will be understood, however, that the form of the grinding element upon which my device may operate may be varied. Spindle 20 is driven in any suitable manner, for'vexample, sheave 26 and belt 28. Now referring more particularly to the elements by which the actual grinding isveffec ted ;a dressing point 30 (which in prac tice usually consists of a small pin with a diamond fragment mounted in it) is mounted in a bar 32 which has a pin 34 secured to its rear end. This dressing point contacts the grinding wheel ata point which is approximately diametrically opposite to the point of contact of the grinding wheel with the hob. One advantage of this is that the construction is thus more compact and also the dressing point may contact the grinding wheel at the same time that the latter is in contact with the hob. The hob does, not have to be removed before the truing' can take place. The pin is arranged obliquely to its line of travel, that is, obliquel to the temp-' let 48, hereinafter mentione and conseuently it is oblique to the line of contact of t e dressing point on the grindin wheel. As a result, a sharp corner of the diamond or dressing point may always be presented to the grinding wheel by rotating the pin on its axis to a fresh angular positlonwhen the diamond has become worn. The bar 32 fits slidingly in a channel 36 formed in the .side of a block 38 shown in vertical section in Figure 5. This block forms a housing for the bar and permits the latter to slide freely in it both longitudinally and laterally. The side of the channel is closed by a plate 40 which is screwed or otherwise side of the housing. The rear end of the housing 38 has slots 42 above and below the channel. These are arranged longitudinally in the block and form guides for pin 34. It will be evident that by sliding the pin in the slots 42, the bar 32 will be moved longitudinally.

This sliding movement of the pin is accomplished by means of a lever 44 which is fulcrumed on a pin 46 secured in housing 38. Said lever is bifurcated at its inner end to engage pin 34, as well illustrated in Figure 6. By rotating the lever about its pivot the pin 34 will slide longitudinally in the slots 42.

The diamond point is held to its work by a. templet 48 which engages a contactor or wearing pin 50'screwed into the back of arm 32. The working edge of the templet (which of course may have various contigurations) determines the final configuration of the work. The wearing pin is at all times held in contact with the working edge of the templet by means of a leaf spring 52 which is mounted on the inner side of plate 40 and prese's against the side of arm 22-2. Templet 48 is slidingly mounted in housing 38 at the side of arm 32. According to the present design the templet consists of a comparatively thin bar of metal as well shown, for example, in Figure 5. The housing has a shallow channel 54 for accommodating it. The templet has a. slot 56 within which is a coiled compression sprin 58. This spring is contained in a cylindrical socket 60 in housing 38 as clearly shown in Figure 4. The arrangement is such that the spring constantly urges the templet toward the rear end of the housing (thatis, toward the right, Figure 4).

The rear ed e of the templet is beveledand is engaged b an adjusting screw 62 having a knurled ead 64 and lock nut 66. The latter abuts the rear end of the housing. On account of the beveling of the rear end of the templct the action of spring 58 is to constantly urge the templet toward the right Figures 5 and 6 (that is, toward the bot-tom of the slot in which it is slidably mounted). By adjustin the screw 62 the tcmplet maybe adjusted longitudinally. thusenabling an desired portion of the tcmplet to be broug t within the zone of action of the wearing pin 50. The templctis backed up bv an ad usting screw 68 which is proride with a knurled head T0 and screws within the stem 72 of the housing 38. In

the preferred construction, which is well illustrated in Figure 6, the housing 38 and its stem 72 are integral. It will be evidentthat by manipulating the screw 68 it will secured to the and thus vary the degree of bevel produced in the work.

The stem 72 is here shown to be cylindrical and is prevented from rotating by arms '7 6 which form part of the'frame 10 and constitute keepers in which housing 38 may slide. Housing 38 and stem 72 constitute what may be termed a sub frame mounted in the main frame 10. Stem 72 is slidable within the housing 74 and its position longitudinally is determined by a feed screw Ti'which works in an internally threaded socket 78 in the stem, as best shown in Figure 6. This screw has a collar 80 .near its outer end which abuts a plate 82 screwed or otherwise fastened to the rear end of housing 74. At the outer end the screw has a knurled head 84, the hub of which abuts the outer surface of plate 82. Thus when the screw is rotated it will shift the stem 72 longitudinally but will itself be prevented from moving longitudinally.

The operation of the mechanism has already been dcscribed in detail and it will be suflicient to say that when the parts have been assembled as illustrated in Figures 1 and 6 and elsewhere set rotating at high speed and the diamond pointwill then be moved forward and back along the surface of the rapidly rotating rinding wheel by oscillating the lever 44 ack and forth about its axis -16. The wearing pin 50 will, of course, slide along the working edge of the templet 48, and the path of the diamond point will be a counthe spindle 20 will be terpart of that portion of the working edge of the templet over which the working pin travels during the course of the movement. As the grinding surface wears away the diamond point may be made to follow it, up by rotating the feed screw 7 6. This will advance the parts without changing the degree of bevel in the work. In fact the whole housing 38 may be removed from the frame and then replaced'without changing our adjustment. i

\Vhile my device may constitute a separate and individual truing mechanism, I employ it in practice in the form of an attachment to a hob grinding machine such. for example. as is shown in my companion application filed May 3, 1923. Serial No. 636,323. In the mechanism there illustrated the pedestal 1 constitutes'the tool post of the machine. It will be evident that my mechanism is excecdingly simple and reliable. As the entire framework is here shown as being in the form of a single piece. the structure re.- mains rigid and reliable at all times. By employing it in connection with the tool postof a hob grinder my apparatus may be placed and withdrawn as a unit. It is possible to make very fine adjustments for it will be evident that where a templet is employed back and forth about'its axis.

in which the workin edge is straight the taper may be accurate y controlled by means of the adjusting screw 68 in connection with the adjusting screw 62. These adjustments need not be disturbed when the apparatus is placed in or taken from the hob grinding machine nor need they be disturbed when the feed screw 7 6 is rotated in one direction or another to bring the pressing point' towardior from the 'work.' After the adjustment has once been made the movement required of the operator is quite simple, for all he has to do is to oscillate the lever 44 The spring 52 keeps the wearing pin in contact with the templet during the various positions of the latter and also serves to prevent the bar 32 from swinging out of contact when the work is not present. The device as an entirety will thus be seen to be both convenient to use and accurate in its work, and capable of maintaining a given angle while one specimen of work is removed and another positioned.

It will be observed that the parts are so proportioned and arranged that the grinding wheel and the dressing tool are in line with the axis of the pivotally mounted main frame 10. It will also be observed that the axis of the grinder spindle, the line of movement of the stem 72 and the pivotal axis of the main frame lie substantially in a common plane and are oblique each with respect to the other. It will also be noted that the stem 72 occupies an intermediate position between the axis of the grinder spindle and the pivotal, axis of the main frame. Also it will be noted-that the contactor 50is located directly behind the dressing tool 30. These characteristics produce a most compact and simple construction. They also make it ossible to bring the dressing tool readily 1nto and out of engagement with the grinding wheel. The necessary movement is very slight and yet the truing mechanism is at all times out of the way of and free from interference with the object to which the grinding wheel is to bev applied.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. Truing mechanism having a bar, a housing in which said bar is encased, said bar being both longitudinally and laterally movable in the housing, a dressing point projec'ting from one side of the bar near one end, a. pivot near the opposite end of the bar, a tem let arranged alon side of and behind the liar fixed relative y thereto during truing, a eontactor rejecting from the back of the bar directly ehind the dressing point, and means mounted on the housing for sliding the bar longitudinally to cause the dressing point to travel over the surface of the grinding wheel to be trued.

-2. Truing mechanism havin a bar pro vided with a dressing tool an a contactor at one end thereof, located on opposite sides and substantially in line with each other, a housing in which the bar is freely movable both longitudinally and laterally, a templet 4 extending lengthwise and behind thebar in positionto be engaged by the contactor, the end adjacent to the contactor bein freely movable in the same plane as the ar, the opposite end of the templet being pivoted at a fixed point thereon on the housing during truing, and means for adjustingthe free end of the templet toward and from the contactor.

3. Apparatus of the class described including a frame having a tool holder su port by which a grinding toolma e .axis and the axis about which the wheel support turns, and adjusting means mounted on the frame and operative upon said stem for moving the stem to acting and nonacting position for moving the dressin tool into and out of contact with the grin er.

4. Truing mechanism having a main frame, a grinding wheel supporting spindle rotatably mounted in said frame, a sub frame a bar provided with a dressing point, said bar being freely slidable in a given plane in said sub frame, a templet backing up said bar, said templet being adjustable in the same plane as the bar for moving the dress ing point toward and from the grinding wheel, an adjusting screw for adjusting the tem let longitudinally, and a spring forhol ing the templet incontact with the adjusting screw, the sub frame having a hearing surface and the rear end' of the templet being bevelled whereby when engaged by the adjusting screw, it is held in contact with the bearing surfacein the frame.

5. Truing mechanism having a grinder to be trued, a main frame which is pivotally mounted upon a horizontal axis extending approximately through the grinder, a grinder spindle, a'casing in which it is journaled, means forming part of the main frame for holding said casing at an oblique angle to the axis of the mainframe approximately in a plane passing through it, a dressing tool having a dressing point for engaging the grinding wheel at a point diametrically opposite to the point of contact of the grinding Ill wheel on the work, a sub-frame ad'ustably mounted in the main frame, a bar or supporting the dressing point, means for guiding the bar relatively to the sub frame, and means for moving the bar longitudinally in the sub-frame at an angle oblique to the axis of the main frame and oblique to the axis of the grinder spindle, and on the opposite side of the main frame axis from the grinder spindle axis.

6. Truing mechanism having a main frame which is pivotally mounted about a horizontal axis, a grinder spindle for supporting the grinder to be dressed, a casing in which the grinder spindle is journaled to rotate on an axis lying approximately in a. plane passing through the axis of the main frame, means forming part of themain frame for supporting said casing and holding it at an oblique angle to the axis of the main frame and holding the grinder approximately in line with the axis of the main frame, a dress ing tool having a dressing point for engaging the grinding wheel, and a support for holding said dressing point for engaging the grinding wheel, a sub frame adjustably mounted in the main frame, and a support mounted in the sub frame for holding said dressing point incontact with the grinder at a point diametrically opposite to the point of application of the grinder to the work, said sub frame being slidably mounted in the main frame to adjust the dressing point toward and from the grinding wheel, said "sub frame being movable rectilinear-1y in a direction oblique both to the axis of the grinder spindle and the axis of the main frame, and along a line located between the spindle axis and the axis of the main frame.

7'. Truing mechanism having a main frame, a spindle for supporting the rinding wheel to be dressed, a casing in w rich the spindle is journaled, means on the main frame for supporting the casing, a dressing tool, a bar for supporting said tool, a contaetor mounted on' the bar on the o posite side. of and approximately in line with the dressing tool, a templet for controlling said contaolor, a sub frame movably mounted in the main frame for supporting the bar and templet and moving the dressing tool toward and from tho-grinding wheel, and means tactor on the supporting element, a templet for backing up the contactor, said templet at one end being movable toward and from the grinding wheel and at the other end sli'dable longitudinally, and meansfor adjusting the movableend of the templet toward and away from the eontactor for varyiug the angularity of the path of travel of the dressing point relatively 'to the axis of the grinding wheel.

9. Means for dressing grindin comprising a main frame in which t 1e grinding wheel is supported. a sub frame movably mounted in the main frame, a dressing point, a supporting element for the dressing point, a eontactor on the supporting element, a templet for backing up the contactor, said templet at one end being movable toward and from the grinding wheel and at the other end slidable longitudinally, means for adjusting the movable end of the templet toward and a my from the contactor for varying the angularity of the path of travel of the dressing point relatively to the axis of the grinding wheel, and means for moving the sub frame as a whole toward and from the grinding wheel.

10. In a hob grinding machine, a combined grinding and dressing unit having a rigid frame adapted to hold the grinding wheel in contact with the hob, a sub frame mounted in the main frame and adjustable along a line oblique to and in the same plane as the wheel axis and as the axis of the main frame and located between said axes, a bar having a dressing point on the front and a eontactor fastened to the back, a templet behind said bar for guiding the contaetor, and means for reciprocating the bar to slide the eontactor along the templet.

In witness whereof, I have hereunto subscribed my name.

CHARLES J .IRWIN.

wheels" 

